What do the spider and butterfly really mean in the movie?

As everyone knows, in the movie there appears a spider about to devour, but what exactly does that mean?

secrets

Many think it's Reze luring Denji into her trap, but it's actually Makima, and Reze represents the spiderwebs she uses to attract Denji... those of us who have read the manga know what will happen.

Reze is the spiderweb she uses to achieve her evil plans... one of many.

race

The type of butterfly that appears in the film is the monarch butterfly, and the type of spider is the brown recluse (Loxosceles reclusa), both very venomous species, but the butterfly's venom is more lethal and if consumed by a predator, it will cause its death. How prophetic, right?